linux-kernel - Re: [PATCH v4 7/8] usb: typec: ucsi: Support mode selection to activate altmodes

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Message-ID: <aWkAx-QjfwQGJ6Eb@kuha>
Date: Thu, 15 Jan 2026 16:59:19 +0200
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Andrei Kuchynski <akuchynski@...omium.org>
Cc: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>,
	Benson Leung <bleung@...omium.org>,
	Jameson Thies <jthies@...gle.com>, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, chrome-platform@...ts.linux.dev,
	Tzung-Bi Shih <tzungbi@...nel.org>,
	Guenter Roeck <groeck@...omium.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
	Łukasz Bartosik <ukaszb@...omium.org>,
	Abel Vesa <abel.vesa@...aro.org>,
	Pooja Katiyar <pooja.katiyar@...el.com>,
	Johan Hovold <johan@...nel.org>,
	Hsin-Te Yuan <yuanhsinte@...omium.org>, Madhu M <madhu.m@...el.com>,
	Venkat Jayaraman <venkat.jayaraman@...el.com>
Subject: Re: [PATCH v4 7/8] usb: typec: ucsi: Support mode selection to
 activate altmodes

Tue, Jan 13, 2026 at 01:05:35PM +0000, Andrei Kuchynski kirjoitti:
> If the ucsi port driver supports modes selection, it should implement
> `add_partner_altmodes` and `remove_partner_altmodes` ucsi operations. With
> these operations the driver can manage the mode selection process.
> Once partner altmodes are registered, `add_partner_altmodes` is called to
> start the mode selection. When the partner is unregistered,
> `remove_partner_altmodes` is supposed to stop any ongoing processes and
> clean up the resources.
> 
> `typec_altmode_state_update` informes mode selection about the current mode
> of the Type-C connector.
> 
> Signed-off-by: Andrei Kuchynski <akuchynski@...omium.org>
> ---
>  drivers/usb/typec/ucsi/ucsi.c | 11 +++++++++++
>  drivers/usb/typec/ucsi/ucsi.h |  4 ++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index deb210c066cb5..4a6e23b55b10c 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -314,6 +314,7 @@ void ucsi_altmode_update_active(struct ucsi_connector *con)
>  {
>  	const struct typec_altmode *altmode = NULL;
>  	u64 command;
> +	u16 svid = 0;
>  	int ret;
>  	u8 cur;
>  	int i;
> @@ -335,6 +336,10 @@ void ucsi_altmode_update_active(struct ucsi_connector *con)
>  	for (i = 0; con->partner_altmode[i]; i++)
>  		typec_altmode_update_active(con->partner_altmode[i],
>  					    con->partner_altmode[i] == altmode);
> +
> +	if (altmode)
> +		svid = altmode->svid;
> +	typec_altmode_state_update(con->partner, svid, 0);
>  }
>  
>  static int ucsi_altmode_next_mode(struct typec_altmode **alt, u16 svid)
> @@ -609,6 +614,8 @@ static int ucsi_register_altmodes(struct ucsi_connector *con, u8 recipient)
>  			desc.vdo = alt[j].mid;
>  			desc.svid = alt[j].svid;
>  			desc.roles = TYPEC_PORT_DRD;
> +			desc.mode_selection = con->ucsi->ops->add_partner_altmodes &&
> +					con->ucsi->cap.features & UCSI_CAP_ALT_MODE_OVERRIDE;

Can't you just use that con->typec_cap.no_mode_control flag here?

Maybe also consider squashing that patch 3/8 into this one while at it.

>  			ret = ucsi_register_altmode(con, &desc, recipient);
>  			if (ret)
> @@ -831,6 +838,8 @@ static int ucsi_check_altmodes(struct ucsi_connector *con)
>  	if (con->partner_altmode[0]) {
>  		num_partner_am = ucsi_get_num_altmode(con->partner_altmode);
>  		typec_partner_set_num_altmodes(con->partner, num_partner_am);
> +		if (con->ucsi->ops->add_partner_altmodes)
> +			con->ucsi->ops->add_partner_altmodes(con);
>  		ucsi_altmode_update_active(con);
>  		return 0;
>  	} else {
> @@ -1119,6 +1128,8 @@ static void ucsi_unregister_partner(struct ucsi_connector *con)
>  		return;
>  
>  	typec_set_mode(con->port, TYPEC_STATE_SAFE);
> +	if (con->ucsi->ops->remove_partner_altmodes)
> +		con->ucsi->ops->remove_partner_altmodes(con);
>  
>  	typec_partner_set_usb_power_delivery(con->partner, NULL);
>  	ucsi_unregister_partner_pdos(con);

thanks,

-- 
heikki